Vertical tabs in FF

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
#tabbrowser-tabs {
    background: #000000 !important;
    border: none !important;
    margin-top: none !important;
    border-radius: none !important;
    padding: none !important;
    min-width: 25px !important;
    overflow: hidden !important;
}
#verticaltabs-splitter {
background: #000000 !important;
}